An Approach for Groundwater Plume Delineation

Product releases from underground storage tanks are in many cases very localized (point-source) and occur rapidly. When all or part of the released product reaches groundwater in a homogenous and isotropoc soil, the spreading of dissolved constituents is susceptible to analytic modeling. Based on minimal data requirements: (1) soil hydraulic conductivity and porosity; (2) longitudinal and transversal dispersivities; (3) amount, time and location of product release; and (4) groundwater level gradient, it is possible to develop a predictive methodology for the spatial and temporal migration of dissolved product. This work develops an analytical equation for approximate plume delineation. The relevance and usefulness of this method for site characterization and corrective planning are highlighted in this paper. An example illustrates the applicability of the analytical approach advanced in this work.